common: Move reset_cpu() to the CPU header

Move this function out of common.h and into a relevant header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/nds32/lib/interrupts.c b/arch/nds32/lib/interrupts.c
index 88cc7b9..1481e05 100644
--- a/arch/nds32/lib/interrupts.c
+++ b/arch/nds32/lib/interrupts.c
@@ -10,6 +10,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <irq_func.h>
 #include <asm/ptrace.h>
 #include <asm/system.h>